The density concurrent matrix is an important characteristic for texture analysis. In the conventional method, it takes a long time to generate a density concurrent matrix. The density concurrent matrix is a two dimensional expression of the relationship between the density of each pixel and densities of other pixels.
A conventional method is to shift an image by a predetermined distance and then to compare corresponding pixels of the shifted and unshifted images. For this process, much process time is necessary when done by software. A plurality of scans is necessary, at least equal to the number of density levels. When one scan is performed of a video frame, it takes about one second for processing an image of 16 density levels.